Building structure



FIG. 1 is a top view of my building structure;

FIG. 2 is a cross-sectional view showing the interior of my building structure;

FIG. 3 is a rear view thereof;

FIG. 4 is a frontal view thereof; and,

FIG. 5 is a bottom view thereof. 

The ornamental design for a building structure, as shown and described. 